$: The current set of characters after which a string may be broken to fill continuation fields (starting with ^) in a format. The default is " \n-", to break on a space, newline, or a hyphen. You cannot call format_line_break_characters() on a handle, only as a static method. See IO::Handle. Mnemonic: a "colon" in poetry is a part of a line.

$< The real uid of this process. You can change both the real uid and the effective uid at the same time by using POSIX::setuid() . Since changes to $< require a system call, check $! after a change attempt to detect any possible errors. Mnemonic: it's the uid you came from, if you're running setuid.

$0 Contains the name of the program being executed. On some (but not all) operating systems assigning to $0 modifies the argument area that the ps program sees. On some platforms you may have to use special ps options or a different ps to see the changes. Modifying the $0 is more useful as a way of indicating the current program state than it is for hiding the program you're running. Note that there are platform-specific limitations on the maximum length of $0 . In the most extreme case it may

$/ The input record separator, newline by default. This influences Perl's idea of what a "line" is. Works like awk's RS variable, including treating empty lines as a terminator if set to the null string (an empty line cannot contain any spaces or tabs). You may set it to a multi-character string to match a multi-character terminator, or to undef to read through the end of file. Setting it to "\n\n" means something slightly different than setting to "" , if the file contains consecutive empty l

$. Current line number for the last filehandle accessed. Each filehandle in Perl counts the number of lines that have been read from it. (Depending on the value of $/ , Perl's idea of what constitutes a line may not match yours.) When a line is read from a filehandle (via readline() or <> ), or when tell() or seek() is called on it, $. becomes an alias to the line counter for that filehandle. You can adjust the counter by assigning to $. , but this will not actually move the seek pointer

$- The number of lines left on the page of the currently selected output channel. Mnemonic: lines_on_page - lines_printed.

$, The output field separator for the print operator. If defined, this value is printed between each of print's arguments. Default is undef. You cannot call output_field_separator() on a handle, only as a static method. See IO::Handle. Mnemonic: what is printed when there is a "," in your print statement.

$+ The text matched by the last bracket of the last successful search pattern. This is useful if you don't know which one of a set of alternative patterns matched. For example: /Version: (.*)|Revision: (.*)/ && ($rev = $+); This variable is read-only and dynamically-scoped. Mnemonic: be positive and forward looking.

$* $* was a variable that you could use to enable multiline matching. After a deprecation cycle, its magic was removed in Perl v5.10.0. Using it now triggers a warning: $* is no longer supported. You should use the /s and /m regexp modifiers instead. Deprecated in Perl 5. Removed in Perl v5.10.0.

perlvar NAME DESCRIPTIONThe Syntax of Variable Names SPECIAL VARIABLESGeneral Variables Variables related to regular expressions Variables related to filehandles Error Variables Variables related to the interpreter state Deprecated and removed variables